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What to do when you accidentally land on a runway thats borderline long enough to land on?
I was reading another question earlier when I noticed a story about a 737-700 that landed at M. Graham Clark Downtown Airport in downtown Branson Missouri.  The runway is only 3738 ft, long, which is a bit short for that particular kind of aircraft.
Apparently the pilots set the aircraft down hard and immediately did everything in their power to bring the craft to a halt, stopping about 500ft short of the far end of the runway (which, btw, ends in a cliff.  Just to heighten the suspense).
I'm sure they had their reason, so I'm not going to question them.  I just wanted to use it as a set up for this question:
If you accidentally touch down on a runway that is borderline long enough to stop your aircraft on, how would you determine if you wanted to either stop or just do a touch and go?  Is it too late once you've already touched the ground?

Ah, to set auto-spoilers/brakes for bringing the aircraft to a halt in the least amount of time/distance or not to have the best chance of a successful touch and go? Tough choice isn't it?

They stopped in just over 75% of the runway? Seems plenty long enough for me!

@JonStory Well, it was in favorable conditions, which isn't really what runway requirements are calculated for.  If it had been raining, foggy, icy, windy, etc...  Might not have ended so well.

In terms of safety, the key mistake was made as soon as the pilot made the decision to land on that runway. The corrective emphasis should be on determining why this mistake was made and taking whatever steps are necessary to prevent that mistake in the future. Especially in transport category airplanes, the crew should always calculate the required landing/rollout distance for the current landing weight, wind, atmospheric (temperature/pressure) and runway surface conditions, and this should be compared against the approach plate / airport diagram / A/FD. In most transport category airplanes this can all be computed by the FMS and it is standard procedure to do this on every single flight.
The question of what to do after the key mistake is still valid, though. I would say it depends on when the pilot recognizes that the runway is too short.

If recognized on approach, a simple go around is clearly called for and perfectly safe.
Once the wheels touch the ground, the decision gets a lot more complicated. The pilot must choose whether to reject the landing or commit to it. If you recognize it as soon as you touch down, you would probably be able to apply takeoff power and get airborne again safely. Once you've started to brake and decelerate, there will quickly come a point-of-no-return. Since you're starting at high speed, you're using up a lot of runway early in the landing rollout. Also note that in many airplanes it can take a significant amount of time to retract spoilers, stow thrust reversers, and spool the engines back up to takeoff thrust. You'll be consuming a lot of runway during this time. (At a constant 120 knots, you'll use up 2,000 feet of runway in just 10 seconds.)

In my opinion it's far better to commit to a landing. If I'm going to overrun the runway, I'd rather it happen at low speed. If you try to take off again and don't make it, your overrun will be at much higher speed, and destructive energy in a crash is proportional to the square of your ground speed.
So there's a gray area... you could attempt to take off again if you were dead certain you were going to make it. Otherwise, it's most likely best to "cut your losses" and get the airplane as slow as possible when you run out of runway, in order to minimize damage & injury. If you can get it down to, say, 30 or 40 knots, you're likely to escape without any serious injuries (the plane may take a bit of a beating, though, depending on what's beyond the end of the runway). If you do it at 120 knots, all bets are off. And you did mention a specific runway with a cliff at the end; obviously that would have to factor into the decision-making process. It may be that you simply realized your mistake too late and there is nothing you can do about it.
This leads me back to the original point, which is that the key mistake was made as soon as the pilot decided to set up an approach to that runway. The best bet is to make sure that never happens.
EDIT: After reading about the specific incident you referred to, it seems that the pilots simply mistook the airport itself for a different one with a longer runway. So it's not necessarily that they failed to calculate their required landing distance; rather they just landed at the wrong place. This is a different, but equally bad (or worse) mistake, discussed to some extent in the comments below.

Many airlines have a policy that once reverse thrust has been initiated, you are automatically committed to the landing for exactly the safety reasons you mentioned.

@BretCopeland If you'd like to elaborate on how airline policy factors into the decision making process (perhaps in another answer) I'd love to hear it.

@BretCopeland Some AFM's contain that limitation as well....

@JayCarr I don't have anything else to add. dvnrrs gave a great answer, and I was just adding a minor point, which comments are good for.

Just for extra-scary points, here's what can happen if you don't commit: http://en.wikipedia.org/wiki/American_Airlines_Flight_625

Yeah, the edit is correct. This was a scheduled Southwest Airlines flight. The scheduled runway was plenty long to land the aircraft safely. Unfortunately, they lined up on and landed on the wrong runway at a different airport. A similar incident happened a few months before that with a Boeing Dreamlifter (a modified 747 designed to carry parts for the 787) landing at the wrong airfield in Wichita. The mistake was failing to identify the correct runway, not failing to ensure that the destination runway was long enough.

@reirab -- jeez, how do you do that?  Nobody noticed?  The pilots, the ATC, nobody?  Those two airports are 8 miles apart, and the M. Graham Clark Downtown Airport is, as you'd guess, downtown.  I hope that alcohol was involved, because I don't like to think that anyone was this dumb sober.

@Malvolio - I actually live pretty close to both airports, and have seen both from the air.  I can actually see how visually one might, possibly, make that mistake...  M. Graham does look like a small version of Branson Regional in a lot of ways.

@Malvolio - for comparison: http://en.wikipedia.org/wiki/Branson_Airport

@Malvolio, As I recall, due to their distance from the radar installation, the radar couldn't see them for the last few minutes of flight, since their altitude was below its horizon. The pilots obviously didn't check their navigational instruments closely, since they would have made it obvious that they were headed for the wrong airport. Visually, I can see how the mistake could be made. 8 miles seems like a long way on the ground, but it really doesn't when you're in the air. At approach speed for a 737, it's a difference of less than 4 minutes flying time.

When flying (as a passenger) on approaches into Nashville, I can see my home town that is over 80 miles from our position and can spot and identify each airport over a roughly 90 mile radius, especially at night. I can see how it would be easy to line up on the wrong runway if you were flying purely visual, but it does seem odd that they seem to have completely ignored all of their navigational aids (and probably charts, too.) They must not have even tuned to the ILS or it would have clearly indicated the error. Glancing at the GPS and/or a VOR/DME should have alerted them to the problem, too.

More than once a Heavy cleared to land at Stewart-Newburgh (SWF) 27 (11817 feet) has tried to land at Dutchess County Airport (POU) 24 (4999 feet). Always exciting for people in the area. airnav.com says "DUTCHESS COUNTY ARPT LCTD 3.3 NM SW IGN VORTAC; DO NOT MISTAKE FOR STEWART INTL."

The same thing used to happen to people landing at Opa Locka (OPF) instead of Miami International (MIA) and also at San Diego Brown Field and Tijuana.  It was particularly bad at these because the runway layout was the same and the airports are close together.

If you accidentally land on a runway chances are you have no idea whether it is long enough or not for either a touch and go or a landing, and you aren't going to be able to figure it out in the time you've got either. For me the answer of what to do depends on what you are flying.
If you have a high thrust to weight ratio the safer option may be to set maximum power and try to climb out of it, providing there's no obvious clearance issues. So if I'm in a P-51 I throttle up and set a maximum climb rate speed. Otherwise the best option would be to treat it as a short field scenario and use every means at disposal to remove as much energy from the aircraft as quickly as possible, while warning passengers to brace.
If you survive, go to a mechanic in the local FBO and ask him/her to kick you in the butt as hard as they can for being an idiot.

"go to a mechanic in the local FBO and ask him/her to kick you in the butt as hard as they can for being an idiot." Usually this service is free of charge, and sometimes you don't even have to ask for it!

Yes, one of the few free things in aviation these days!

To answer the "title" question (not the detailed questions below):

Approach with engine idled (which will mean the plane will be nose-down until you flare)
Touchdown at slowest safe speed, hopefully just past the end of the runway
Brake hard - really hard
Retract flaps
Push down the nose
Basically you are trying to get as much weight onto the wheels as quickly as possible, which maximizes the effectiveness of your brakes

Excellent.  Is there any difference between how this might work for a jet versus how it might work for a regular piston aircraft or a turboprop?

I would say that in jets you generally have reverse thrust and spoilers to help out. Whether flaps should be retracted would be a good question.

@fooot I mostly ask because the engines aren't nearly as reactive as a prop engine, so...wondered how that might change things.

A jet engine should probably also be at idle, both for minimal thrust and to allow soonest deployment of thrust reversers.

Or better yet, follow the short field landing technique in the AFM.  :-)


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Is it possible to build a jet engine that utilises all excess heat?
Is it possible to build a jet engine that utilises excess heat for thrust or does not produce any excess heat hence no need for cooling which is wasted energy

You cannae change the laws of physics.

No, any thermal machine always transfers energy from the heater to the cooler (Carnot cycle). The maximal yield depends on the temperature difference and cannot achieve exactly 100%. It is equal
$$
1-\frac{T_\text{C}}{T_\text{H}}
$$
where Tc is the temperature of the surrounding air and Th is the temperature of the burning fuel. Jet engine as normally understood in aviation is a thermal machine.

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What are the effects of adding winglets to an aircraft not designed with winglets originally?
Are there any positive advantages or catastrophic effects on adding winglets to an aircraft not designed with winglets originally?

kind of related: https://aviation.stackexchange.com/q/31551/1467 https://aviation.stackexchange.com/q/8556/1467

All B-737's coming off the production line now have winglets, although for the longest time, the B-737 didn't have winglets.  So there are plenty of those jets flying around now that had them retrofitted, which is exactly what you're asking as far as "adding winglets to an aircraft not designed with winglets originally."  The advantage to adding the winglets was in reduced fuel burn; there were (obviously) no catastrophic effects in adding them, and some fairly minor engineering issues that were addressed.

I heard a story about the A320, that because of production tolerances (and possibly the uncertainty of the calculations) they made the original wing spar much stronger than necessary. As such, there is quite some reserve in the strength of the spar, and they could add the winglets without replacing the wing. In essence, this means that the strength to support the winglets was provided by having smaller strength margins.

@RalphJ That looks like most of a decent answer.

Aircraft wings are designed for specific weight and cruise speed. When later the manufacturer wants to create a new variant with higher maximum weight, it should get longer wings for optimal efficiency. However, redesigning the wing is a lot of work, because extending the wing means the root bending moment increases, which requires stronger spar, which means heavier and all the calculations have to be redone.
Here is where winglets get useful. They increase the effective wingspan, but while they are somewhat less efficient than extending the wing, they also cause lower increase of the root bending moment. Often, this smaller increase fits in the original extra margin, so winglets can be simply bolted on without having to redesign the wing, making the process much cheaper.
That's why we often see winglets on next generation of anything and rarely on the first generation. On first generation, they are designing the wing from scratch anyway, so they just make it appropriate length for minimum drag.
The main reason to use winglets from the start is if the emerging design just slightly exceeds some size category for airport gates. Then it makes sense to reduce the span to fit and add winglets so the aircraft can be used at smaller—and therefore cheaper and more common—gates.
You can read how winglets work in Is a winglet better than an equal span extension?.

Isn't the "winglets not on the first generation" thing more the result of those first generations being designed before the benefits of winglets were appreciated (NASA research around 1980), and the increasing cost of fuel made retrofitting them cost-effective?

@jamesqf, no, because designs created after 1980 either don't have them (B777, B787), or have only small ones (A330, A380).

I helped install winglets on 4 B757's a few years ago, I cannot remember the exact figures, but by fitting the winglets we improved the fuel burn for flights over 3000 miles by about 8%, over less than 2000 miles the fuel burn actually increased and made the aircraft less efficient by approximately 4%. So it can sometimes be a trade off.

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Is it feasible to recuperate energy from landing aircraft by using a runway sled with regenerative braking?
Would it be feasible to land large (Boeing 747 and Airbus A380) and all other aircraft on a sled on the runway, the kinetic energy of the aircraft is then transferred to the sled, then the sled uses regenerative braking to produce electricity for use by other electric sleds that taxi the aircraft to the runway for taxi, given that a lot of fuel is used during taxi and that fuel is expensive, causes green house gas pollution when burnt. This would save costs on tire wear brake pad wear and if designed properly improve braking safety

Note that regenerative braking will only recover the equivalent of 0.025% of the fuel capacity of an airliner, which is quite insignificant.

Sure it's feasible.  But outside of la la land where the astronomical costs of putting in this kind of elaborate infrastructure, not to mention redesigning the entire airplane to recover like this, with limited movement options vs MUCH cheaper and mature alternatives such grooved concrete or asphalt runways and conventional landing gear and brakes.

Such schemes have been considered before, most recently the GABRIEL project. But the foreseeable technical and logistical problems with such a scheme are formidable. Personally, I think you are more likely to see pigs learn to fly!

It would be simpler to attach a tail hook (like aircraft carriers) and use a cable to brake the aircraft to run regeneration motors. Either way it isn't a feasible source of power for an airport. A mini nuclear power plant would be a whole lot easier to implement.

How would you accelerate the sled - other than by having the plane collide with it? If you use power to do it, well, that defeats the purpose a bit...

Aircraft don't all touch down at the exact same spot on the runway. Therefore, the sled would have to move to match the speed of the incoming craft (using energy from...) waiting for the craft to settle on it. Once settled, the regeneration could kick in and that might produce enough energy to get the next sled moving for the next aircraft, but it would be highly unlikely that it would generate enough to taxi the whole plane back to the gate with engines off.

In decelerating from, say, 550 kts to 130 kts for landing about 75% of the kinetic and potential energy has already been lost and is not recoverable. The whole idea is daft. How would the plane grip the sledge? How would the plane stay on the sledge as it braked? What would happen if the sledge jammed? How would you get the plane off the sledge?

I don't understand why this question has been voted down. It's not a stupid question. It's not off-topic. It's clear, and it has a clear answer. The fact that the answer is no this would not be a good idea doesn't make it a bad question.

There are really two completely separate and unrelated ideas here: using the kinetic energy of landing aircraft to generate electric power; and using electric power for taxiing.

What you propose might be technically possible, but that doesn't make it a good idea.
However, any benefits would by tiny compared to the immense cost, the extraordinary engineering efforts required, and the horrendous risk of something going wrong.
Airports have long, wide runways for good reasons. Airliners don't touch down on a single spot. Your "sled" would need to be a very wide and extremely long platform.
The sled would need to be able to bear the weight of a large airliner as it touches down. A large plane can damage a concrete runway. The sled is going to need to be extraordinarily strong.
Your platform will need to accelerate from zero to the speed of a landing airliner in very short order; if it causes the plane to decelerate too rapidly instead, it will tear bits off the plane, or limbs and heads off the passengers.
Good luck designing and manufacturing this huge, strong and and extremely lightweight sled.
(Maybe you can design the sled to match the speed of the incoming plane. That would solve some problems, but only at the expense of introducing some even more exciting new ones, like having just constructed the world's largest and most lethal railgun.)
What's going to happen when something goes wrong? You now have a wheel-less airliner, in difficulties, at landing speed, plus a huge sled also possibly travelling at 300+ km/h. I don't even want to be in the same town as that, never mind at the same airport.
What will you gain? Not much in the way of saved energy from regenerative braking; the energy cost of maintaining the machinery that can cope with such savage braking effects will greatly outweigh it anyway.
And actually, taxiing is good for aircraft engines, because it allows them to warm up before being used at full power (it may even be good for them after landing, to allow them to cool down more slowly).
So, nice idea, but in this case, the wheel, all of 5000+ years old, is an invention better-suited to airliner landings.

To put some numbers around the answer by @Harper. According to this page, a 737-800 has a max landing weight of 144,00 pounds (65,000 kg) and landing speed of 155 knots (~80 m/s).  That's E=0.5 m v^2 = 0.5 *65000 * 80^2 = 208 MJ of energy. 1 kW-hour is about 3.6 MJ, so we are talking 57 kW-hours.  A kW-hour of electricity sells for about 10 cents.  So there is about \$5.7 worth of energy in a jet liner landing, assuming that your system was 100% efficient.  Once you take into account efficiency losses, you are probably talking \$2.80.  That is so small compared to how much the system would cost, it is not worth it.
(edit: dropped the factor of 1/2 in the energy calculation originally, so it's even less money than I originally said).

On landing - There's no energy in it - airplanes aren't that heavy.  If you're thinking there's \$1000 of energy there, forget it... there might be \$1 worth on a 737.  That's figuring accelerating the platform to meet the plane, aero drag on both platform and plane, rolling resistance, and the sheer difficulty of storing a 50MW surge of energy you'd get catching a loaded 747. The battery pack alone - it'd be much cheaper to pay for an extra windmill at a wind farm, paint "Danzig airport" on the blades, and call it done.   Given the shabby returns, the extreme safety risk of catching an airplane on a sliding platform is not worth it. Arrestor wires would help on all fronts but there's still only a couple bucks of energy there.
Actually the real win for such a platform system would be ground ops.   Plane lands on its own, takes a high-speed exit to clear the runway for traffic, taxis onto a platform, and shuts engines down. The platform then shuttles to the apron or gate.  This solves one of the biggest safety problems in aviation: the ground game, giving railroad-style positive movement control.  It will also save a ton of fuel because aircraft won't spin up engines until near takeoff, and would shut them down immediately on landing - cutting hours off engine runtime and overhaul intervals.
I don't know how I'd feel about using a platform for takeoff, the safety win would be positive movement control (never this) and being catapulted to airborne before V1 decision point. But, many things to go wrong.
The platform would be powered via induction, slot rails (like DC trolleys) or surface current collection and would have a "startcart" onboard which could provide standby power, HVAC and bleed for engine start.

As others have mentioned, there is an issue in terms of what you get back, and the complexity and cost of building a sled to catch the airplane. But there are other issues as well which will be affected by such a change. You'd have an issue with moving the plane afterwards; once landed, do you keep the plane on a sled and move that around (costing lots of energy, changes to infrastructure, capacity issues if you run out of sleds), or do you move the plane off the sled and if so, how? Ramps may work, but takes a lot of area to avoid having to steep inclines, and there might also be a time penalty compared to the more conventional land-taxi-park.
It is unlikely that the sleds can reuse the runways as-is, so you might have to build separate runways for aircraft landing on sleds and those landing conventionally or taking off. Will it be possible for planes to cross the sled runway? If not, some airports will be handicapped (to say the least) as there might not be enough room to build taxiways around. And in any case, taxi times will increase if you can't cross, unless you build the sled-based runways away from everything else (increasing cost as you need more area for the airport).
Some parts of the world experience weather ranging from -30C with lots of snow and wind, to +30C with lots of water. How will the sleds handle that without breaking down? What if the sled breaks down during a landing roll; what will the effect be on the aircraft sitting on top?
This is just a few thoughts I had as a result of reading what others have posted. Everything boils down to cost. Complexity is not an issue by itself, but a more complex system will also have a higher maintenance requirement and more failure modes, driving the cost up. And while todays system isn't perfect, the combination of cost, complexity and flexibility is better than anything else that has been thought of or tested so far.


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What is the effect of sudden extreme temperature change on brake disks of large aircraft?
What is the temperature of brake disks at maximum altitude of a jumbo like a 747 and airbus A380 for say a 10 hour flight.  Does the temperature drop below zero and what is the effect on the metal material used on the disk from the sudden change in temperature from one extreme, below zero degrees celcius to over 700 degrees celcius when braking?

Brakes are designed to handle rapid temperature increase from extreme to another (e.g. rejected takeoff at V1 on a cold airport). Problem arise when the brakes are not cold enough (some airecrafts are equipped with brakes fan to decrease brake temperature during short gate stops)

Keep in mind that some types of brakes need a certain amount of temperature to be effective!

See also: https://aviation.stackexchange.com/questions/33024/what-is-the-temperature-of-the-brakes-after-a-typical-landing

Closely related (duplicate?): https://aviation.stackexchange.com/questions/33716/how-are-brakes-cooled-on-heavy-aircraft/33717#33717

The temperature changes from altitude to ground are not (usually) rapid. Therefore the possible sub-zero to red-hot case is not as severe as may be thought. If carbon discs are the example, they require temps that are almost beyond steel discs braking capability.

Agree  with Lokwyr, in fact with these disks the higher the temperature the better the braking.

Until they burn up anyway, see this brake test clip https://www.youtube.com/watch?v=m1dv_y_3EK0

Having worked in a wheel and brake shop for years and being an ATP Airline pilot for most of my career I can tell you that brakes won't freeze up unless there is moisture present. Even taking off on snow and flying long hours at high altitude will not cause a problem.
Brakes are a machine. They turn kinetic energy into heat. Here is the problem. It is not the rapid change of temp but the temp limit at which they can continue to function and dissipate the heat at the same time. This is why manufacturers print brake energy charts. Once the limit has been reached, they must be cooled for the period stated or they can no longer stop the aircraft. The factors that matter are OAT, aircraft weight, runway length and prior immediate applications. Not all are considered in the calculations as some are not as critical. The manufacturer doesn't usually tell you the runway required, they just block off that part of the chart where braking effectiveness becomes nil.

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What is the flap adjustment angle for delta wing Aircraft for take off?
What is the flap adjustment angle for delta wing aircraft for take off for
the Concorde and the SR-71 Blackbird, given that it has no horizontal stabilisers and that it used elevons?

Concorde did not have any flaps or slats as mentioned here. This is due the fact that they don't have any tails, and wing trailing edge devices do the elevator and aileron jobs and they are called elevons.

in essence only slats are adjusted


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Is this scaling of aircraft size and power (at least roughly...) correct?
I use to fly a very light plane, with a 100-hp engine. In order to calculate the power needed by a similar plane, but 50% larger, I reason as follows:
In general, the power required by an airplane is proportional to its weight times its speed. The weight scales with the cube of the linear dimension, so the larger plane would weigh 1.5 cubed = 3.375 times more. Since the airspeed is squared in the formula for lift, the exponent for the proportionality of lift should be 1/2.
I have now two exponents for the scaling, 3 for the weight (or mass, in this case) and 1/2 for the speed. As the weight and speed are multiplied in order to get the proportionality of the power required, I add the exponents, and the result is that the larger plane would need an engine of 1.5 ^ 3.5 = 4.13 x 100 = 413 hp.
Is this OK?

For a first order of magnitude check your result looks good.
Experience tells that the mass scales not quite with the length cubed, so an exponent between 2.3 and 2.6 gives better results. Wing area goes up with the square of the length increase, so your wing loading will become
$$\frac{m_{large}}{A_{large}} = \frac{m_{small}^{2.4}}{A_{small}^2} = 1,176\cdot\frac{m_{small}}{A_{small}}$$
This requires 8.44% higher speeds. To achieve them, thrust must go up with the square of the speed increase and power with its cube, since power is thrust times speed. Therefore, the power increases by a factor of 3.375 if the mass scales with the exponent 2.4. Power loading will now be
$$\frac{P_{large}}{A_{large}} = \frac{3.375\cdot P_{small}}{A_{small}^2} = 1,5\cdot\frac{P_{small}}{A_{small}}$$

Assuming that length, width, and height of all dimensions are scaled up uniformly, and assuming that weight scaled with L^3, and assuming that the lift and drag coefficients of your wing remain the same, then I don't see anything wrong with your number.


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For a rotor in vertical autorotation, what is the relation between pitch, vertical speed and rpms?
In other words, what happens to vertical speed and rpms in vertical autorotation if I change the pitch of the blades of the gyro I use to fly...?

Please forgive a perhaps stupid question, but doesn't autorotation imply zero thrust?

No. You have a thrust exactly as the weight of the gyro. That's why it descends (in vertical autorotation) with a constant speed, and not accelerating... Thanks to your answer, I've now realized that the thrust is constant, so I'm now editing the question, changing 'thrust' with 'vertical speed'

@qq jkztd  You're wrong. Think in a falling skydiver. When he reaches a constant, terminal speed it's because the drag force is the same as the weight of the skydiver. Otherwise, an acceleration would appear... The same happens in vertical autorotation, with the only difference that the rotor gives a thrust, not just rough drag...

@qq jkztd  Wrong again... There are two annular zones in the autorotating rotor, the driven one (which overcomes most drag and produces most lift) and the driving one (that absorbs energy from the upward-flowing air, converting it to power to drive the rotor). Both zones produce thrust, if it's true that the driven one (the outward ring) is responsible for most of it.

On a modern (Bensen/Wallis type) gyro, you can't change the pitch of the rotor blades.

@You can. It may be more or less difficult, but far from impossible. And in some gyros you have even a collective lever....

@qq jkztd  Sorry, but I'm not going to continue discussing this. Please allow me to say that you should learn and understand some elementary physics concepts.

For what it's worth, when conducting routine maintenance test flying, Autorotation is performed in order to check the auto rpm. Helicopter manufacturers specify an rpm range for autorotation. If the rpm is too high the pitch change links (pcl) are adjusted to increase collective blade pitch. If the auto rpm is too slow, pcls are adjusted to decrease collective pitch. most pilots and flight departments prefer the rpm to be at the high end of the range, allowing additional rotor energy options for the pilot. This technique must not be overdone else collective authority in the flare/touchdown will be adversely limited.

Unless I am misinterpreting your question, if you add pitch [pulling collective in a helicopter] your RRPM [rotor RPM] will decrease, as it is being used to accelerate air down decent, if in a vertical decent the aerodynamics are screwy. Now if you have some forward speed increase Pitch trades RRPM for lowering vertical speed. Decreasing Pitch, allows you to trade altitude for RRPM giving you higher VS and higher RRPM.


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Are modern aircraft provided with analog consoles in case of a software failure?
I am curious about the redundancy they provide in modern era commercial aircraft.
Here are the questions:

If an aircraft suffers partial or complete software malfunction, do the pilots have the choice of flying the craft with help of analog consoles for critical systems(e.g. speed, altitude, heading indicators and basic flight controls). It summarizes to the point whether they provide such analog devices ?
In case of such failure, can the engines keep running so as to provide thrust, fuselage pressurization and breathable air supply to cabin?

I read somewhere that for the A320 in case of complete electrical failure the trim wheel can be used for basic pitch control. You may also consider flight control describe in this wikipedia page

All commercial aircraft have some form of redundancy in their instrumentation, but it's not always in the form of "analog" instruments. The backup is often electronic itself. But the overall system is designed with a very high level of redundancy.
A typical modern jet aircraft has an Electronic Flight Instrument System (EFIS), which is the large screen Primary Flight Display (PFD) you see in front of both pilots. There are usually also one or more Multifunction Displays (MFDs) in the middle between the pilots. These displays form the primary instrumentation.
The EFIS itself is designed with a very high level of redundancy between the pilot's and copilot's side displays. Both are on independent electrical circuits and receive information from independent input computers (air-data [ADC], attitude/heading [AHRS], etc.). Both can usually also be switched over to the other set of input computers. Usually, the MFD can also be configured in a "reversionary" mode where it looks and acts like a PFD.
If the entire EFIS system should fail, there is also a backup set of instruments. In modern times this backup is usually one or two Electronic Standby Instrument Systems (ESIS). These are essentially smaller, condensed "PFDs" that display critical information. They usually either contain their own miniature AHRS/ADCs or are connected to isolated computers. They are also powered on a totally independent electrical circuit and often have their own dedicated battery as well, separate from the main aircraft battery.
Modern engines are controlled by completely different computers called Full-Authority Digital Engine Controllers or FADECs. Two or more FADEC channels are provided for each engine, so that if either channel fails, the other can take over. FADECs are also considered flight-critical items, and are designed with fail-passive capability: even if both FADEC channels fail, the engines can still run and be controlled more primitively and less efficiently.
Electronic pressurization controllers don't always have redundant computer modules, but a manual pressurization control mode is always provided. In the worst case, the pilot has the ability to manually open or close the cabin outflow valve to control cabin pressure. And redundant pressurized air sources are available from each engine.

Aren't airliners required to have at least one independent, analog backup instrument (the standby navball)?

Surprisingly, whilst most combat aircraft are jam packed with fall back analog instrumentation, despite often being aerodynamically unstable and requiring fly by wire to actually fly (SU-27 for example), many modern airliners do not even though they are actually stable and can be flown manually (Go figure!). They do however, have multiple resilient systems as stated by dvnrrs above, and importantly, pilots use (Or should use) a "cross-check" in the event of instrument failure. So, if for example IAS is lost, then ground speed, engines, pitch, etc. should be used instead.
This subject has been discussed in depth, and with massively serious consequences since the French Airbus disaster Flight 447. Reports of flight 447 show that airspeed information was lost as one of the critical factors leading up to the accident. Increased pilot training and systems will be coming I think to help mitigate future failings like occurred on that tragic day over the Atlantic ocean.

The Airbus in Flight 447 had redundant airspeed sensors which all got iced over. One major problem with that flight was, like you mentioned, the inability of the flight crew to cross-check (there was plenty of indication of stall, such as an excessive rate of descent). Fly-by-wire and computer assisted controls are not one and the same, however (all Airbus planes are fly-by-wire). The unstable design of all modern fighter jets is due to the designers' desire to make those aircraft highly maneuverable, fly-by wire is simply a means to an end.

Thanks to the fine work done by TsAGI, the Su-27 is stable over its whole angle of attack region. This is quite an achievement in itself, considering that most western designs really need computer control to fly at an angle of attack of more than twenty-something degrees.

In addition, on AF447 the plane automatically de-iced one of the air speed sensors 1 minute after the lost of all the 3 sensors so the plane actually had all the information required. The pilots panicking still took the plane to the sea. I think they would have been fine if one of the pilots had just re-enabled the autopilot. That alone speaks loads of inadequate pilot training.


text:
Which CS-23 airplane has the lowest takeoff speed?
Among the currently certified CS-23 airplanes (or "Part 23" in FAA-land or your personal region equivalent), which has the lowest rotation speed ($V_r$)?


text:
Were there civilian female test pilots in the 60's?
In 1962, women couldn't become astronauts because NASA had a requirement that astronauts be experimental jet test pilots. In the 60's, were there any civilian test pilots that tested planes that weren't jet planes? Were there any female test pilots that tested planes that weren't jet planes?

I looked for the US (as you also mentioned NASA) without success, but as you're asking for names worldwide I'm replying with famous French test pilots that come to my mind.
Were there any female test pilots that tested planes that weren't jet planes?
In France the first women to test planes, Adrienne Bolland, did it in 1920, indeed this was on aircraft with piston engines.
Were there civilian female test pilots in the 60's?
Jacqueline Auriol worked as a test pilot for Brétigny flight test center from end of 50s and till 71. In 1962 she set her fifth world speed record.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Dyke Delta dynamics?
I recently came across the Dyke Delta, designed by John Dyke. It is a delta wing (more like diamond planform) homebuilt. I'm curious about how this airplane handles, considering delta wings have some particularities.
Specifically:

How does the Delta Dyke achieves pitch stability, without an horizontal stabilizer? Most delta wing airplanes have long chord wings, so a little elevon trim can be used, but the Dyke has short chord wings, so is pitch stability a problem?

Does it have flaps? If so, how effective are they, would they interfere with the pitch attitude?

Delta wings are notorious for high take-off and landing speeds, because they generate less lift at low airspeeds. This is usually made up for with vortex lift created by by an aggressive angle of attack, like Concorde. But as far as i've seen, that doesn´t happeb with the Dyke. So how does it handle short take-off/landing with a normal angle of attack?

How does the Delta Dyke achieve pitch stability?

See the rear part of the wing as an elevator which happens to be attached to the wing. The elevons are trimmed slightly trailing edge up, so this rear part produces less lift per area than the forward part. Stability is achieved naturally as explained here.

Does it have flaps?

No, flaps would increase lift per area at the rear wing and make the plane unstable. Only leading edge devices are possible in tailless designs with little sweep, but not employed in the Dyke Delta. With enough wing sweep, flaps can be used inboard but must be combined with more trailing edge up trim on the outer, more rearward wing. See the Horten IX / Go-229 for an example with inboard flaps.

Delta wings are notorious for high take-off and landing speeds ... So how does it handle short take-off/landing with a normal angle of attack?

as the linked Wikipedia article explains:

Its stall speed (70–75 mph) is relatively high for a small single-engine aircraft, and its configuration at touchdown is relatively nose-high. Approach speeds of 100–110 mph are used.

Being an experimental design, the Dyke Delta does not need to conform to FAR 23 which demanded a minimum speed no higher than 61 knots. It basically skirts the rules to allow for a higher landing speed and lower pitch attitude during landing. Still, the low aspect ratio results in a fairly high nose-up attitude.

The thing could do 180mph on 180 hp, pretty impressive for a 4 place airplane. But too many negatives to get more than a few builders keen on the funky looks interested. I +3 seating, can't see the ground from the pax seats, the fast landing speeds. Just too much of an oddball. A BD-4 was a more practical contemporary choice,

@JohnK The 3rd passenger had to be small to fit on the rear bench, so not a real 4-place airplane. And a high top speed is easier when you keep wing area too small for 61 knots - Rutan used the same tricks.


text:
Arinc 429: how to detect the data frame start?
I am designing an Arinc429 receiver based on a micro-controller with two interrupt inputs served by a circuit converting the +/-10V standard signals into two separated 0-3.3V streams, respectively firing at every logic "1" and "0".
The interrupt service routines then encode (fill) an array with 1 or 0 accordingly to the Arinc429 input data.
The system is logically correct and works nicely with an emulated stream but only because it comes when the array index is reset to zero. In principle in the real world case it could instead start accumulating data anywhere in between the 32 bit word. Then it would never synchronize again with the data transmission.
How can I know that an incoming bit is a new 32-bits data word start, or, in other words, how could I detect a new data frame start?

I feel this should be transferred to Stack Overflow or Drones and Model Aircraft

@AadirajAnil I believe ARINC 429 related questions are best asked and answered here

I believe this question should be declared as on-topic. It is about the ARINC 429 protocol which is exclusively used in aircraft. Whilst going deep into engineering details, to a level that could also fit at electrical engineering stackexchange, the Aviation-industry-specific nature  of ARINC 429 makes it likely that people with the required specific knowledge are in this community. Additionally, by welcoming people from the engineering domain, we all learn about the technology that makes us fly. I will not vote-to-reopen because as a mod my single vote is decisive, it's up to the community.

ARCINC 429 uses a tristate voltage level, high at 10 V, low at -10 V and a null at 0 volts. There will be 4 bit lengths of null voltage between 32 bit messages. in the message, a high will be 10 V followed by a return to null. a low will be -10 V followed by a return to null. The time of the bit lengths depends on the transmission rate, usually 12.5 K bits per second or 100 K bits per second.

I was missing the 4-bit lengths of null voltage between consecutive messages. This allows to properly detect the next message start with proper firmware modifications. Jim's comment helped a lot, thanks.


text:
Can an instructor with an Instrument Airplane Instructor rating instruct for PPL?
I'm graduating from college this May, and as a graduation gift, I'm planning on getting my FAA PPL. I'm wondering if my father (with the FAA ratings below) could be my instructor for the 20 hours of dual flight. If not, what specific rating would he need to obtain to be able to be my instructor?
AIRLINE TRANSPORT PILOT:

AIRPLANE SINGLE ENGINE LAND

COMMERCIAL PRIVILEGES:

AIRPLANE SINGLE-ENGINE SEA
AIRPLANE MULTIENGINE LAND

FLIGHT INSTRUCTOR:

INSTRUMENT AIRPLANE

Your dad cannot provide any flight training without a category and class on his flight instructor certificate.  He will need to take a practical test to add the category and class onto his flight instructor certificate for the airplane you want training in.

§ 61.195 Flight instructor limitations and qualifications.
A person who holds a flight instructor certificate is subject to the following limitations:

(a) Hours of training.  In any 24-consecutive-hour period, a flight instructor may not conduct more than 8 hours of flight training.

(b) Aircraft ratings.  Except as provided in paragraph (c) of this section, a flight instructor may not conduct flight training in any aircraft unless the flight instructor:

(1) Holds a flight instructor certificate with the applicable category and class rating;
(2) Holds a pilot certificate with the applicable category and class rating; and
(3) Meets the requirements of paragraph (e) of this section, if applicable.

It is also true for training in a simulator, FSTD or other such devices.
Beard Interpretation

The rules changed in 2012.  Hence, the question on the ability to use the sim with only a CFII.  Before that date, you could instruct instruments in the category you had the instrument privileges for.

Not in an aircraft.  They can teach instrument ground schools through for the instrument category they hold.


text:
What is the regulation(s) that states GPS can be used in lieu of DME? Pertaining to the US
I always hear that GPS can be used in lieu of DME, but I would like to know the specific regulation that states this.

In the U.S.  it is found in the AIM 1-2-3.

For the US, this is part of AC 90-108 "Use of Suitable Area Navigation (RNAV) Systems on Conventional Routes and Procedures"

7.a: Usage of Suitable RNAV Systems. Subject to the operating requirements in this AC, operators may use a suitable RNAV system in the following ways
(1) Determine aircraft position relative to or distance from a VOR (see first note in subparagraph 7b), TACAN, NDB, compass locator (see second note in subparagraph 7b), DME fix; or a named fix defined by a VOR radial, TACAN course, NDB bearing, or compass locator bearing intersecting a VOR or Localizer (LOC) course.
(2) Navigate to or from a VOR, TACAN, NDB, or compass locator.
(3) Hold over a VOR, TACAN, NDB, compass locator, or DME fix.
(4) Fly an arc based upon DME

Summary on the AOPA site: Use of GPS in lieu of DME/ADF.
Note GNSS in lieu of DME doesn't include approaches, like ILS/DME. In these approaches the DME may be located at any suitable place, e.g. at the mid point of the runway length, and its 50 µs response delay recalibrated to indicate 0 at the threshold of the active runway. Something the GNSS cannot handle without additional information.


text:
How prevalent is traditional radar tracking of commercial aircraft?
In many media reports regarding air incidents such as AirAsia Flight QZ8501: What We Know About the Missing Plane from NBC News I often see a phrase such as the following:

By the time it had been given clearance, just four minutes after its last correspondence, the jet had disappeared from radar, Tjahjono told the news agency.

From various maps I've seen it appears the aircraft went missing over 100 km from any major land masses / airports and it made me wonder how far commercial aircraft would normally be tracked by traditional radar that sends a ping and waits for an echo from a typical airport?
I'm guessing in many cases media tend to use the term radar interchangeably with transponder technologies such as ACARS but I'd still be interested to know the limits of typical radar installations and how prevalent it remains in modern commercial aviation.

I probably should have referenced that related question but what the answers don't address is the typical range for primary radar at a commercial airport. I wasn't sure of their capabilities or if they are still widely used at most airports.

The link came across to a different question to the one I selected!  I'll fix it.  Try this as well http://aviation.stackexchange.com/questions/2291/where-is-the-airspace-not-covered-by-primary-radar

possible duplicate of http://aviation.stackexchange.com/questions/115/what-is-the-range-and-accuracy-of-atc-radar-systems

There are many surveillance technologies available to track aircraft.
Radar is the most common technology used for ATC (Air Traffic Control) surveillance. Basically there are two varieties:

Primary radar
This type of radar sends a high energy radio pulse which reflects of the aircraft. The time delay of the received echo is a measure of the distance.
The characteristics of the transmitted radio pulse. Since aircraft don't have to participate for this radar to work this radar principle is mostly used for Air Defence purposes.
ATC primary radar usually has a maximum range of about 50-100NM, but can exceed 200NM. Primary radar is mostly used for airspace protection (monitoring unauthorized access) and airport surface control. These radars have a limited maximum range but a very low minimum range and provide reasonable accuracy.
Long range primary radar is expensive to operate. Due to the free space signal loss, long range radar needs to transmit a very powerful pulse and receive an very weak echo. The associated infrastructure (large antenna, active cooling) and power requirements make long range primary radar very expensive.
Military use of primary radar includes over the horizion (OTH) radar which has ranges well over 1000NM. These radars are geared towards detection of incoming missiles and aircraft and not suitable for air traffic control due to their lower accuracy.
Secondary radar
Secondary radar is the most common surveillance technology used by ATC.
This type sends a radio signal to the aircraft's transponder to which the transponder replies with its own radio signal. Again the time delay is a measure of the distance. The transponder can encode additional information about the aircraft (such as altitude or identity) in the reply. This radar technology relies on the correct functioning of the radar transponder.
Because the radar relies on transmission of energy from the aircraft, the transmitter needs less power than a primary radar. The maximum range of secondary radars can exceed 250 NM for aircraft flying high enough (above the horizon). Not all secondary radars are operated at that range though, airport radars are often limited to 50 - 100 NM.

Radar signal horizon

Then there are a number of surveillance technologies which are a bit different than radar:

(Wide Area) Multilateration
This technology uses multiple receivers spread over an area. By accurately comparing the times that an aircraft's transponder signal arrives at the different receivers the system can calculate where the signal must have been transmitted from. The transponder signal must be received by at least four receiver to get an accurate position. The accuracy of multilateration is best in the area surrounded by receivers; outside that area the accuracy of the system degrades quickly. A provide with enough receivers, a Wide Area Multilateration system can cover vast airspace volumes.
ADS-B
Automatic Dependent Surveillance - Broadcast is a surveillance technology that relies on the aircraft transmitting their position twice per second. A simple antenna and receiver is all that is required to receive these positions. Since the signal comes from the radar transponder, the above signal horizon figure applies. A very sensitive receiver can detect high flying aircraft far away. Not all aircraft are yet equipped with ADS-B but most passenger transport aircraft are.
The company Aireon is equipping satellites with ADS-B, so in 2018 there will be oceanic ADS-B coverage.
ADS-C
Automatic Dependent Surveillance - Contract is again a surveillance technology that relies on the aircraft transmitting their position. Contrary to the broadcast counterpart which transmits to all interesting parties, ADS-C addresses its transmissions to the contracted ATC facility. The data goes via a satellite link or over VHF when the aircraft is flying over land. Because of the satellite link, coverage is global (except the poles).
ADS-C reports are less frequent that radar or ADS-B reports, typically the system only reports at specific reporting points.
ADS-C is not installed on every aircraft, mostly on intercontinental transport aircraft. It is used mainly over the Pacific and the Atlantic.
Verbal position reporting
Not really a surveillance technology, but used in areas where there is no other means of surveillance available. The pilot reports his position over the radio to air traffic control. The maximum range of the radio transmission is the limiting factor here. Using HF radio, global coverage is achievable. The transmissions suffer a lot from static noise and sometimes other aircraft have to relay messages if no proper direct communication between ATC and the aircraft can be achieved.

Very good references found in the Wikipedia  article.


text:
Do I need a PPL license for a CPL license?
Do I need a PPL license to get a CPL/ATPL license?
I could not find anything on the net regarding my question.

Yes, with a couple of exceptions. FAR 61.123 contains the requirements for a commercial certificate, while 61.153 contains the requirements for an ATP certificate.
FAR 61.123(h) states than an applicant must:

Hold at least a private pilot certificate issued under this part or meet the requirements of §61.73

FAR 61.73 refers to the option for military pilots to apply for an FAA certificate based on their military qualifications. For non-military pilots, the commercial certificate can only be earned after obtaining the private pilot certificate.
FAR 61.153(d) includes the ability to use a foreign commercial or ATP certificate as a prerequisite. An applicant must:

Meet at least one of the following requirements:
(1) Holds a commercial pilot certificate with an instrument rating issued under this part;
(2) Meet the military experience requirements under §61.73 of this part to qualify for a commercial pilot certificate, and an instrument rating if the person is a rated military pilot or former rated military pilot of an Armed Force of the United States; or
(3) Holds either a foreign airline transport pilot license with instrument privileges, or a foreign commercial pilot license with an instrument rating, that—

(i) Was issued by a contracting State to the Convention on International Civil Aviation; and
(ii) Contains no geographical limitations.

For the European regulations there exist two ways of gaining a CPL:
Way A, also called "modular": Before being allowed to start your CPL training, a PPL is mandatory + night flying permission. In total you need 150h of flight time out of your PPL.
Way B, also called "integrated": A flight school offering modular courses does not neccessarily be able to offer integrated courses, so clarify beforehand. Offering such integrated courses requires special school certification. This course, however, get's you to receive a CPL/IR from pedestrian to commercial pilot without any intermediate stop. Having a CPL, you are authorized to perform the rights of a PPL.

Are the requirements for the integrated path similar to the modular path but without the paper work to get the intermediate PPL license during the course?

When you do your integrated training you will end up with less hours compared to a modular student. Mostly, also in a shorter period of time. The integrated course simply aims at the CPL/IR multi engine,solely. Though, the flying and technical requirements stay the same. When you do modular training each license itself is supposed to be useful on its own (first PPL, second IR single and multi engine rating, third CPL single and multi engine).

@BSteinhurst effectively the "integrated" path combines both training and examination paths into a single course, fast tracking the candidate.

You definitely do.
You get your certificates in following order:

PPL
CPL
ME
ATPL Frozen ( This is actual license for becoming and FO)
ATPL ( It means you are eligible to become Captain)

Not necessarily, I got Commercial and ATP without ever having a PPL.

@MichaelHall see LRT's answer. You probably got an implicit PPL as part of an integrated course.

@jwenting, nope, I was military.  See Nathan G's answer.

@MichaelHall in that case your military license counted as a PPL equivalent.

@jwenting, incorrect.  First, there is no such thing as a military pilot license.  And if there were you would be unable to exercise PPL privileges with it.  There is no military occupational specialty designation equivalent to a PPL.  You can make a case for commercial, but not private.


text:
Do landing strips suffer from landing wheel tire tracks?
I've now seen several landing strips up close and there are lots of tire tracks from planes' landing wheels. I wonder if it somehow modifies the properties of landing strips to make for poorer landing conditions.
Do landing strips suffer from lots of tire tracks?

It does indeed degrade performance, and runways (and their lights) have to be routinely cleaned of rubber. The FAA specifies safe friction levels.
Wikipedia has this to say:

The build up of rubber affects the level of friction of the runway, most noticeably as a reduction in braking and ground handling performance. This can lead to incidents such as runway overrun or a lateral slide off the runway.

Some runways are particularly poor:

you'd expect rubber on rubber to have better grip than rubber on asphalt/concrete

@ratchetfreak maybe not rubber on water on rubber? Also rubber has a tendency to melt when it gets too hot, making it very slippery.

And perhaps it can be more grippy in some situations, but perhaps all that does is cook the brakes?  Sometimes overheating brake pads will cause them to fade a bit...  Though in reality @ratchetfreak, I'm similarly baffled.

@jay doing some research it seems that a smooth surface is indeed more susceptible to aquaplaning

It's not rubber on rubber, but rubber on rubber dust. Dust can almost act as a lubricant!

Also, the rubber on asphalt or concrete has the advantage of the rubber pushing into the small holes in the surface. This greatly increases the coefficient of friction (i.e. more traction.) When the texture of the surface gets filled up by rubber dust, that advantage goes away.

The Runway friction level is affected by accumulation of rubber deposits (in the touchdown zone) on the runway. Periodic removal of the deposits is needed to maintain the highest possible friction level. On busy runways rubber deposit accumulation if inevitable, runway maintenance needs to address this. When the actual runway friction level is below the minimum friction level, a 'slippery when wet' NOTAM is devised or another runway is designated.
Detailed information about friction, measurement and contamination can be found here.
As a side note: next to rubber deposits the paint used for markings on runways and taxiways contains a certain amount of sand to increase its friction.

How is the rubber deposit removal done? Mechanically, with rotating brushes of some kind perhaps?

@florisla How is tire rubber removed from the runway?

Oh yeah it certainly does as I learned one rainy day.
The A7-E Corsair is a single seat jet attack plane for the Navy. They were deployed aboard carriers in the mid 1980's. It needs at least 10,000 feet of runway to land. On a wet runway the pilot is required to take the wire, or divert to another field because it won't stop in time.
I always found the stopping distance of the A7-E to be remarkable. The brake system on the A7-E incorporated anti-skid, however they were undersized for the aircraft and therefore the necessity for long roll-outs.
I was flying in to NAS Sigonella in Italy with the carrier air-wing close behind. There were over 20 planes headed for the field. As I came in to the runway it was raining off and on, and the air temperature was hot. Going VFR at the initial, below the clouds, I did a touch and go, and rolled out looking over the runway surface. It was relatively dry with no standing water, and so opted not to take the gear on the runway. I assumed that it was the heat of the runway that evaporated most of the water.
The arresting gear was laid across the runway at the both ends and if an aircraft required it, they lowered their tail hook on the approach, and snagged it as the ran over the wire. Taking the gear took some consideration though since it took at least 15 minutes to reset if personnel are well trained. In Sigonella's case not many planes take the wire and so it might take 30 minutes to reset. For one plane! And there are another 20 plus coming soon.
I came back around and landed. After slowing down I tested the braking, still having time to go around. It was good. I relaxed and coasted toward the end at around 60 knots. When I got into the tire marks it was time to slow down for the turn off, and it was like being on ice. Nothing! I turned the nose gear with the rudder and the aircraft indeed turned, but kept sliding straight down the runway. Disconcerting to say the least. After the rain, the oil had risen to the surface of the skid marks, forming a film there.
Entered the area were the skid marks disappeared and the plane came to a stop. Wow, that was a surprise.

Nice story but I'm a little confused as to whether the surface was wet or not.  Re-reading I guess it was dry.  Also can you explain what "and so opted not to take the gear on the runway" means?  Does this mean that you land beyond the wire?  Or that the wire is not lifted up into position?  Or that the plane's tailhook is not lowered?  Anyway thanks for the account.

Edited the text. The runway was dry with no standing water. It had been raining off and on and the runway was hot. Arresting gears, if the airport has them, are typically located at both ends of the runway. After you land you will roll over the gear and if your tail hook is down you will take the wire. The roll out is very gentle compared to the ship :) If your hook is up you just roll over the wire and continue down the runway.

"It needs at least 10,000 feet of runway to land" - I've always wondered... why? High landing speeds? Bad brakes? No ABS? Modern aircraft have no problems, I've seen F-18s land in something I wouldn't consider in the Arrow. So is it one thing, or a combination of things?

The landing speed of an A7-E was somewhat fast, between, as I remember, 125 and 145 knots. It did have ABS, however the braking system was undersized for the aircraft. This, I was told, was the reason for the long roll-outs. We had to be very careful to not overheat the brakes and end up blowing the fusible plugs on the flight line.


text:
What is the proportion of active aircraft from CASL (commercial aircraft sales and leasing)?
I recently discovered the existence of CASL and I understand they buy a lot of new aircraft (e.g. BOC aviation ordered more than 80 B737's and about 40 A320's few weeks ago). I imagine those aircraft are used for temporary operations (e.g. during scheduled maintenance or waiting for an aircraft to be delivered) by regular airliners, charters, lines with demand growing faster than expected, etc.
Given the number of aircraft they buy, a significant part of the traffic must be operated by these aircraft. Is there some statistics about the number of aircraft and/or the number of flights performed with an aircraft owned by leasing companies compared to flights performed with aircraft owned by airlines themselves?

@fooot I don't know wich one is the more relevant, so both. Question edited accordingly

I won't put this as an answer as I don't have proportions, but CASL companies do several things: long term leasing (like a car purchase) for new or small airlines. Short term leasing for airlines with unexpected demand or hull losses due to maintenance/accidents. They also just straight out sell aircraft, bridging the gap between order and delivery for airlines.

According to The Economist data in 2012 showed that:

Over a third of the world's airline fleet is now rented (see chart)
  and the proportion is likely to keep growing.

The article has some interesting background about the companies involved and the advantages of leasing vs. buying, which one Delta source compares to housing:

[Delta's fleet planner] argues that big airlines are better off buying planes and keeping
  them for their full lifespan of 30 years or so. Like houses, then,
  buying is cheaper than renting in the long term.


text:
How feasible is it to use Smart Materials on aircraft?
Smart or Shape-memory materials have been known for quite long. What factors/limitations are put on it for applications in aircraft?
For someone who doesn't know much about its material properties, it seems quite good to have deforming wing or other parts and seem to improve aircraft performance. (One example might be: suitable wing geometry deformation according to aircraft's speed regime)

As stated by @PeterKämpf, SMAs are only one of many so-termed smart materials (a soft definition in any case). So perhaps you should remove the smart part from your question, as it will be too broad otherwise.

Shape-memory alloys are only a small part of smart materials. Once deformed, they will change back to their old shape when heated or subjected to strong magnetic fields. Of the many alloys with this characteristic, only a few like nickel-titanium would be suitable for primary structures. They are extremely expensive to make and to process, so they have never been an economical alternative.
Also, heating and cooling would be required to switch between shapes, which is very energy intensive when the outer structure of an aircraft is involved. Airflow will ensure intense convective heat transfer, and to maintain the needed temperature will be very uneconomical. Please consider that an aircraft with shape-memory alloys would need to carry extra fuel for heating or cooling over much of the flight time. Hinges and electric or hydraulic actuators will have a clear mass advantage when you consider the system mass, including energy sources.
I guess you agree that creating strong magentical fields in parts of an aircraft is an exceedingly bad idea, so I will rule out magnetic shape-memory alloys.
Shape-memory alloys will only switch between two shapes, and intermediate shapes are easier to realize with hinges and actuators. Sure, a smooth shape is aerodynamically better than one with a contour break at the hinge line, but the small aerodynamic advantage of shape-memory structures is quickly lost when you look at the whole picture.
Another disadvantage is the accumulation of small cracks with every shape change. The low number of cycles will either require frequent replacement of the shape-memory parts or a very limited structural life of the aircraft.
In the end, much of what can be said about other smart materials also applies to shape-memory alloys. Their main function is to justify research grants and to keep the press occupied.

I vaguely remember hearing somewhere that shape-memory alloys are being used for things like pipe fittings in some aircraft. They create a tight fitting from such alloy, stretch it out, put the pipe in and then make it remember its contracted shape (I think it was stretched at liquid nitrogen temperature or something like that) and it seals tight around the pipe and for a joint that can't shake loose like screwed fitting could. But that's one-time use for manufacturing purpose only and for small parts where the durability is worth the extra cost.

@JanHudec: Interesting and well-conceived application of shape-memory alloys. But wouldn't heating the fitting for assembly give the same effect due to thermal expansion? It will need much more heat, though.

I heard it long ago and don't remember much details. I think the point was that it shrinked so much that grooves in the fitting cut into the pipe and that probably needs larger difference in size than is possible with heating without reaching temperature where the material would loose strength.

I also remember it was some fighter, so they wanted to make the thing extra durable and especially easy to maintain, so it warranted even the complicated manufacture (involving some liquid nitrogen) and cost.

SMAs are being used by Boeing in so called chevrons, See this link and this image:

The idea is that these chevrons heat up due to the hot flow coming from the engine. This causes them to deform, and bend into the oncoming flow.
This causes vortices, which will reduce the engine noise by gradually mixing the hot and cold flows coming from the engine.
It should be noted that this is a very different application than the one OP mentioned, as it is non-critical and not a stress bearing part, however, it does show that SMA's can be used in commerical aircraft

Is this a "smart metal" or just bimetallic strips -- like on old thermostats?

I think that the working principle is the same, only that SMA's can be used to deform to a certain shape. As such , to me they are just complex bimetals.

Im not sure this falls under Smart materials but is an interesting side note about shape distortion with heat. The SR-71 stealth plane was subject to such high heat at upper ends of its speed range that the planes panels were actually designed with gaps so that it would not crunch its self to bits when it heated up and expanded. Keeping this in mind you can get an idea of how fast you need to travel to generate enough surface heat to deform the metal substantially (im sure its a bit slower for softer metals).
Back to the topic at hand
Weight is a serious concern as well. Generating heat or substantially cooling a structure at will is no simple task. Such systems would further weigh down an airplane when weight is really the biggest concern in aviation.
Money and well more money is a very real factor in airplane building. FAA type certs are not cheap or easy to come buy and as such commercial aviation tech tends to lag behind what is hot on the market since it takes many years to get an airplane designed, certified and into production. People have been building aluminum airplanes since we had engines powerful enough to make it a reality. Its a light, fairly easy to work with material that has been tried and tested on thousands of airframes flown for millions of hours. We have tooling and shops to make it into what ever we may need. Keep in mind that introducing a new material is not simple. If you would like a current example look at the adoption of carbon fiber which has also been around for some time now and is only just beginning to see use in real commercial aviation on a large scale. Its been used in general aviation for a bit longer since the parts are smaller and a bit simpler to lay up but still more costly than aluminum.


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Is Peter Sripol’s Mk4 ultralight design safe and/or practical?
I recently rewatched Peter Sripol’s Mk4 ultralight video

Obviously, the aircraft flew, but I have several questions as a result.
First and foremost, is a vinyl-covered foam wing with an aluminum spar really safe? If so, is this a practical construction method offering advantages over typical ultralight wing construction techniques?
Secondly, does anyone know what type of foam was used? Would a carbon fiber spar have been better than an aluminum spar? And finally, is there any particular reason that the wings’ internal structure was arranged the way it was?

I don't have a definitive source for this, but I seem to remember from his videos that he uses insulation foam like this for building most of his planes.

That’s what I’ve been thinking as well, just wanted someone to back me up on it. Thanks!

Define “safe”  Which hazards do you have in mind?

As such, I consider this question to be too broad and opinion based. Safety and praecticality should be assessed separately, and quite frankly they are not that easy to define.

@Jim I’m mostly concerned about the strength of the foam wing- clearly it survived the sandbag test and can fly, but it just doesn’t seem right to me.

Peter uses that white polystyrene foam, the stuff used for molded packaging that produces the little white peas when it breaks down, which is pretty weak stuff and I would prefer to use the closed cell polystyrene (Styrofoam SM or similar) that the Rutan designs used, or if there was any chance of fuel or solvents getting near it, polyurethane foam (Quickie 2 builders went with polyurethane for the front wing after fuel leaks that migrated through the fiberglass dissolved the polystyrene in the wing and caused a couple of spar failures).
The stick on vinyl covering probably works fine as long as you aren't taking any credit for it strength wise, and you would need to do your own long term environmental testing to see how it and the adhesive holds up to UV.
The biggest problem with the Mk4 is the 2 axis control.  Roll control by slithering and sliding around, depending on dihedral angle to generate roll rates, is really suboptimal.  It needs more span, most of the dihedral taken out, and ailerons.
The electric power is great, but you are still stuck with about a third of the range of gas engine, pound for pound of all up weight.  Electric power would be more suitable for an ultralight with some soaring capability, unless all you ever expect to do is fly for an hour or 90 minutes locally and land.  A project I'm interested in doing is a Kolb Ultra Star (you can buy scratch plans for it) powered with two 15hp RC motors.

is MK4 ultralight design safe and/or practical?

They did do the sand bag test to 3 G on the wing and corrected the flutter issue on the rear horizontal stabilizer, but a complete structural strength and durability analysis is beyond what was provided in the video. Adding extra wing$^1$ and upgrading the prop definitely seemed to help.
This ultralight was made by scaling up a radio controlled model, which is a good indication that the design or planform will be practical, if not strongly Piper Cub - like.
Key to evaluating "dihedral content" is vertical center of gravity, which on this plane (with its 200 lb wing) is around the pilots head.  There is adequate area below the CG to compensate for the wing dihedral, though 1/3 to 1/2 less might be better.  Mounting the engine(s) higher up (on the wing) would be another way.  Anhedralling the tail, as seen on the Lazair is also possible, but side paneling the fuselage or lowering the vertical stabilizer a bit is much easier.
Tubular aluminum may be stiffer than carbon fibre for the wing spar, but again one may reference a tried and true full scale building technique rather than trying to scale a r/c model.
Overall, with refinements, the MK4 shows promise as a fun-to-fly electric ultralight.
$^1$ adding more wing span will increase "dihedral effect"

I'd expect to see a significantly larger rudder on a plane that is entirely dependent on slip-roll coupling for roll control authority.  In fact that would allow a slightly more modest dihedral angle, making the plane somewhat less vulnerable to crosswind gusts, though naturally an aircraft with two-axis controls (no ailerons) and generous dihedral will always be rather vulnerable to crosswind gusts.  Search the web for photos of early (no-aileron) models of the "Super Floater" ultralight sailplanes for examples of a configuration that might be closer to optimal for an aircraft without ailerons.
None of which means the MK4 would actually be unsafe if flown in appropriate conditions. Just that the window of "appropriate conditions" is quite small.


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What should a pilot do if he does not know where he is and has no form of communication?
I know this is an almost impossible situation, but... Imagine that a pilot is kidnapped and placed inside a Cessna plane. At a certain point the kidnapper jumps out of the plane, destroying the radio and taking all the aeronautical charts with him.
My question is: what should the pilot do, since he does not know where he is (he does not even know which country), there are no signs of civilization where he's flying, and he has no aeronautical charts?

If the hijacker somehow managed to jump out of the plane, then I would assume any sane pilot would do the same considering the chances of making it out of the mess alive.

Time for this -- https://aviation.stackexchange.com/q/75263/34686

Pick a field, land, ask somebody.

This isn't an answer because you said no radios, however the FAA's standard procedure for becoming lost is the 4 Cs: climb, communicate, confess and comply. The last 3 require a radio, though. I agree with Ron: just land somewhere and work it out on the ground. It's a very artificial scenario and I don't know if there's any really useful answer.

It’s a good thing I have ForeFlight on my cell phone.

@DeanF. How nice of the kidnapper to leave you your cell phone :p

You have no means of communication, why would your kidnapper leave your your cellphone?

Because, even kidnappers have a sense of humor. What about this whole scenario makes sense? And, to the kidnapper a cell phone with no signal might not be seen as a threat.

You'd probably enjoy this book about a Vampire jet pilot lost in fog. IIRC the emergency procedure that he follows is to fly in triangles and hope ATC notice, but it's late on Christmas eve. https://en.wikipedia.org/wiki/The_Shepherd

@RobinBennett - There was another question here at AviationStackExchange regarding whether flying in triangles was a legitimate distress signal. I think the consensus was that it was a European thing not duplicated elsewhere.     https://aviation.stackexchange.com/questions/26261/does-air-traffic-control-identify-a-distress-situation-when-an-aircraft-flies-tr

@Dean F.: It might be legitimate in the US - I vaguely recall it from my student days, but that was decades ago.  But it misses an important part of the question: if you have no communications, indicating distress to ATC is pointless - even assuming you're in a location/altitude where there's radar coverage.

@jamesqf - That may be so for the US. But, I can not find a reference for it other than a mention on a Wikipedia page not attributing it to a specific country. The posters in the previous question annotated a reference from UK regs. Would you happen to know of one for the US?

While the kidnapper is removing/destroying the radio, bop him over the head.  He is distracted and won't see the fist/foot/solid object coming.

@jamesqf  -- re " if you have no communications, indicating distress to ATC is pointless - even assuming you're in a location/altitude where there's radar coverage" -- might help to ensure someone will come look for the wreckage after the crash

@quiet flyer: While true, I suggest that would not be a really high priority for most pilots faced with that situation :-)

You are right, this is a pretty improbable situation. But, I will give it a whack.
Aviate - Fly the plane. Fly it at as high of an altitude possible while still keeping visual contact with the ground. Just in case you lose an engine. Fly it in a wide circle or holding pattern until you get your bearings. Slow down your airspeed and lean your mixture for max endurance. You want to conserve fuel as well as ground position. No use in getting more lost quicker.
Navigate - Look for something identifiable. Or at least something that will lead you to civilization and suitable landing areas. Think of it like being lost on the ground. Look for your North direction using the sun or stars. Evaluate the ground for:

High speed avenues of approach like roadways
Key terrain features
Man-made obstacles like towers or buildings

Find water. In the US water towers (not all) are marked with location names. If you find a river, you will usually find civilization close by. If you find a shoreline, you may be able to find a flat area suitable for landing.
Fly downhill. Fly towards the lowering terrain. You are more likely to find a landing area.
If all else fails go IFR (I Fly Roads).
Communicate - If the transponder works, squawk 7600. If you have a cell phone, try it. You May have to descend to get it to work. Only do so if you have established where you are and if the aircraft is safe to continue flight. Turn on all of your exterior lights. If you see an airport, circle directly above the field at 2000 to 4000 feet AGL and look for light gun signals.
Land as far away from the kidnappers/highjackers as possible.

The first thing you should do during a lost com's situation is fly the plane (that is really the first thing you should always do).
The second thing you should do is use visual reference points to figure out where you may be and get some situational awareness. Even in a foreign land a pilot may be able to identify known land marks like city skylines or prominent geological features. Even something like a coast line can be identifying. If the pilot becomes concerned about fuel (which any good pilot will at some point) then they should be on the look out for an airfield or a nice area to put the aircraft down.
The third order of business is to squawk 7600 on your transponder. This will alert any ATC facilities pinging you on radar, that you are unable to transmit and/or hear them.
This falls in line with the FAA's general advice of "Aviate, Navigate, Communicate".
Just a bit of an applicable side note: In the US under the FAA, and in other jurisdictions there are lots of areas that full under "uncontrolled" airspace where no radio or charts are required to be onboard anyway and many pilots are proficient flying in such a situation. Id even go so far as to say that a solid chunk of Piper Cubs are still flown this way.

I think sectional charts or their electronic equivalents are required to be on board in the US even for flights in strictly class g airspace, with the possible exception of a strictly local flight.  Could be wrong.  Could be the basis of another question.

@quietflyer for subpart F "large and turbine aircraft" yes but strictly speaking they are not. 91.103 requires you to be familiar all info which means you would need to at least look at a chart at some point but they are not strictly required.

@ Dave: But the hijacker grabbed all the charts before he jumped :-)

@jamesqf but did he grab the data cards from BOTH of my 430's??? ;-)

Aviate, navigate, communicate.
First, make sure flight is stable. Figure out how long you can do that, and set up flight to maximize that.
Now try to figure out where you can go. From the Question, it sounds like there are no easy answers: no airport in sight, no giant concrete arrows pointing the way, etc. in that case, pick a best direction taking into account terrain, weather, light and wind and start looking for a place to put down. Climb a bit for a wider view if you’re low and can afford it.
Take the first acceptable place, as you’ll want to preserve your passengers (if any), your plane, and even perhaps your remaining fuel.
What about communicate? Well, the problem statement seems to rule that out in flight, but after down SERE training becomes relevant. But that’s another Question...

I think the other answers miss a few points.  I think we can assume the pilot knows where he was when he was kidnapped, no?  So the first thing to do, after making sure the plane is in stable flight, is to check the fuel gauges.  Assuming the Cessna is a 172 with standard tanks, it has 40 gallons usable fuel, enough for about 4.5 hours of flying.  So check the fuel gauges, and see how much you have left.  If the tanks are half full*, then given the 140 mph cruise speed, you can guess that you're within about 300 miles of where you started.  Then start looking for familiar features like mountains, lakes, roads &c, which should be identifiable unless you're over the Amazon Basin or Canadian north.  That will get you oriented, and you can probably find an airport, or some other good place to land.
*If they're close to empty, disregard the rest, and look for a spot to land, or do a survivable crash.

A C172 with reliable fuel gauges?  I suppose there must be one somewhere.

@Dave Gremlin: I wouldn't say reliable - I've never seen a vehicle with fuel gauges I'd really call reliable.  But at least ballpark.  (Better that my Miata, where I can fill up, drive about 250 miles before the gauge shows half full, and then be on empty 100 miles later.)


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C-152 carb heat on before landing in hot weather?
I know the POH for the C-152 explicitly states carb heat should be applied before landing. I fly in a tropical country where temperature is at 30°C on average on the ground, twice the standard temp. Airports I frequent have an elevation at 300' the most. Cruising altitude on most days is between 2500-3500'.
Should I still treat the POH as the bible in this situation, or will the 30°C qualify as an exception?

You can't use temperatures like that. Half of 30°C is 151 kelvin, which is -122°C.

"The temperature outside an aeroplane is six times colder than the temperature inside a freezer"

Why would you even want an exception? It's not like the carb heater is going to overheat anything on a warm day.

You should always pull the carb heat when throttling back no matter the conditions for 3 reasons:

Ice forms from moisture (duh!), and there's much more moisture in hot tropical air than cold arctic air, so being in a tropical location does not lower the icing potential. The temperature drop is caused by the Venturi Effect which aerates the fuel in the carburetor, fuel is not frozen in the carb by the outside air temperature, you can get carb icing on a hot day
Habit: it's important to get into good carb heat habits, otherwise you may forget to pull the carb heat when you need it. Make it so automatic it just happens without conscious thought
Workload: Deciding when to use carb heat or not requires thought, you have to consider density altitude, temperature, relative humidity, the make of the carb, and other factors to make the right decision. Why add to your workload when 90% of the time you're probably going to conclude you do need it? Approach is a busy time, you should be spending time looking for traffic, maintaining airspeed and the other critical aspects of flight

It's worth reminding as well that icing can happen in cruise as well, so keep in the habit of applying carb heat regularly.

Habit: it's important to get into good carb heat habits, otherwise you may forget to pull the carb heat when you need it. Make it so automatic it just happens without conscious thought << This is probably the most important answer to any question in the context of "...it's not needed, should I...".

Because the POH says to. It doesn't say "unless OAT is > 30°C".

Carb heat use is not related to OAT, it's related to moisture and how it can turn to ice in the carb, causing the engine to stop. Carb ice can form at any outside air temperature, which is why you will not find any checklist or POH item for an aircraft with normally aspirated engines telling you to check OAT before activating carb heat. You just do it. I learned to fly on a Caribbean island and I got taken to task by the instructor if I ever dropped power to descend and forgot to turn on carb heat. This does not, however, apply to fuel-injected engines, since they do not have carburetors.

Absolutely right! Warm air holds a lot more moisture than cold.

"Not related to OAT" is a bit of a stretch - "not solely determined by OAT" would be better. There is a temperature drop in the carb but the drop is from the outside air temperature. I make no claims as to whether the carb used on this particular O-235 is guaranteed not to drop the temperature by more than 30 K.

I learned to fly in Louisiana. So while it was usually unlikely to be anywhere close to cold temperatures, it was ALWAYS very humid. And carb heat is usually used during a phase of flight where you don't really want the engine to sputter or quit.

And @pericynthion, I don't know that I'd even say "not solely determined by OAT". I think "OAT shouldn't even be a consideration." is more apt. Don't give a student any reason to think that it's super hot outside so they don't need to worry about carb heat.

@pericynthion Your statement is not correct. The drop in temperature comes from the drop in air pressure in the venturi and the vaporization of the fuel, not from the temperature in the outside air. That is why the use of carb heat is not tied to how hot or cold it is outside. There is no checklist or POH statement for aircraft with normally aspirated engine(s) that calls for checking OAT before turning on carb heat.

I agree that the drop in temperature is due to the pressure (and velocity) change in the neck of the venturi, along with latent heat from the fuel evaporation. But my point is that this is a delta-T that is subtracted from the starting temperature of the air, and that latter is highly dependent on the OAT. The delta-T can be large, and that's why you can get carb ice even at OATs well above freezing.bBut it's not correct to say that OAT doesn't matter. After all, when you apply carb heat all you're doing is raising the temp of the incoming air. A sufficiently hot day would be equivalent.

That's speculation. The bottom line is that we should not encourage any pilot to question the practice, for any reason.

You have mentioned OAT, but remember there are 2 variables for potential icing - the other being Dew Point.

You (roughly) 85F OAT could easily fall into Serious Icing at glide power for a wide range of dew points.

This is a good answer.

It would have been better if the temperatures were in °C, as in the original question.

@Zeus while I agree, at the time this was the only example of this graph I could find, and hence why my commentary converted the original question to F so that accompanying graph could be used

Thou shalt use Carb Heat.
You said you fly in tropical area where the temperature is 30°C.

Warm tropical air has a lot of moisture as others have mentioned.
The venturi effect can drop the air temperature in your carburetor's venturi by as much as 38.89°C (or 70°F) according to this wikipedia article on Carburetor icing.
Thus if you're flying around in ambient 30°C moist air, and it cools down to -8.89°C, you see that the moisture in the air in the venturi will be at a temperature that is well below freezing. (For American audience water freezes as 0°C).

Note: From experience, when the conditions are just right, the carb ice forms within seconds.
Always use carb heat on landing when you go below the green arc on RPM (or as indicated in the POH).
(I don't have the source handy, but I remember reading that warmer ambient temps are actually more conducive to carb ice than very cold ambient temps. If I find the source I'll link it.)

The sweet spot is high humidity, 15-20 deg C.  If you are flying something with a carb that gets almost no radiated or conducted heat at all from the engine, like a J-3 Cub, flying on a 19C evening with high humidity you will just about have to keep the heat on full time.

Most of the temperature drop is from fuel evaporation downstream of the venturi, causing ice from ambient humidity to form on the throttle plate (injected engines also have venturis and throttle plates for fuel and air metering, but because no fuel is being introduced there, so there is no evaporative cooling, there is no need for carb heat and they just use an alternate air source in case of main intake obstruction from other causes).
The temperature drop itself varies with the amount of fuel being introduced, humidity, and throttle opening and like most natural phenomena like this, it forms a bell curve of temperature/humidity, with the middle of the bell curve (highest risk of carb ice) at around 15-20 deg C.  Problem is, that's the middle of the bell curve and the edge of the bell curve can extend to 30 deg C and beyond and you just don't know where you are in it.   On top of that, if it's 30C on the ground, it's going to be just over 20C at 4000 ft, getting you closer to the middle of the bell curve.
So it's somewhat less likely when it's that hot outside, but can still happen and unless you have a carb air temperature gauge that you trust, this is something you don't screw around with and you follow the normal carb heat protocol regardless.
There is a similar situation with the engine itself.  Lycomings are somewhat less prone to carb ice than Continentals because of the way the carburetor connects to the engine (the Lyc carb gets more conducted and radiated heat from the engine because the intake spider runs through the sump, so its body is slightly warmer than a Cont's), but they can still get ice and you follow the same carb heat procedures on either engine regardless.


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Which features identify an aircraft as a "Sixth Generation Fighter"?
I've been seeing all this news about how the Navy and Air force are going to get some new next gen fighter jets soon. However, I was wondering what will be the difference that makes it 6 gen instead of 5 gen. Will it be faster? More stealthy (if that's a word)? Or does nobody know? Thanks!

An extra 0 on the price tag.


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Why is the input power of an ADS-B Transponder much lower than its rated transmission output power?
ADS-B Transponders are usually rated with 150W or 250W transmission power, however the electrical input at 14V is rated much lower, usually around 6 Watt. How can that be?
150 W transmission power with an efficiency of 70% would result in > 200 W input ~ 15 Ampere at 14V. Even if its not CW, there would still be a significant current peak.

Transponders have a low duty cycle. It is limited to 4.5% but that typically only occurs in high interrogation airspace (an area with a large number of secondary surveillance radars and TCAS equipped aircraft.) A typical duty cycle is in the range of 1% to 2%.
ADS-B Mode S extended squitters are 120 usec long and consist of 120 half usec long pulses. So that's equivalent to 0.006% duty cycle for one reply per second. Between interrogation replies (which are about half the length of ADS-B outputs) and ADS-B squitters you're looking at typically 200 to 250 transmissions per sec resulting in a bit over 1% duty cycle.
Transponders typically use capacitors to store up power and a switching power supply to drive the transmitter. Even with an efficiency of 50% (not uncommon in many RF transmitters) you only need an average input of 3 Watts transmit 150W 1% of the time.. At the limit of 4% duty cycle, the power needed would be 12W (but only for a few seconds as the maximum duty cycle only has to be sustained for a few seconds.)
So, yes it is possible to have a transponder only need an average input power of 12W.

The rated TX power is the maximum power emitted while transmitting. The electrical input power is much lower, because the design of the transponder is such that it accumulates energy from the input at relative lower power, to burst that out in one go on the output at high power.
The transmission of a ADS-B extended squitter has a duration of 120 microseconds. Since the modulation is pulse-position modulation, the transmitter actually only transmits for 58 microseconds per message. If the TX power is 250W, a single ADS-B message costs about 0.015 J (assuming 100% efficiency). The maximum squitter rate for ADS-B is 6.2 messages per second, equating to an average of approximately 0.1 Watt of transmitted energy. Other systems hosted by the transponder (Mode S and TCAS) are able to produce easily ten times more messages each. Mode A/C uses much fewer pulses but can have very high reply rates. This brings the average total transmitted power to over 2 W for congested airspace.
Internally in the transponder you will find big capacitor(s) that get charged by the aircraft's electical system, and discharged by the transmitter. They act as a buffer, preventing peak power surges in the aircraft system.


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Should I use given resolution or calculate resolution based on the max range and number of sig bits?
In ARINC429, Should I use given resolution or calculate resolution based on the max range and number of sig bits given?
ForeExample, to calculate Ambient Static Pressure (Label-203, Equipment ID - 10A),
Given Range (Min to Max): 1.5 to 20
Given No of SIG. bits: 11
Given Resolution: 0.016
Calculated Resolution:
MAX RANGE / 2 ^ (No of SIG. bits)
20 / (2^11)
20 / 2048
= 0.009765625.

Question 1: What will be the Ambient Static Pressure value if all the 11 bits are 0.
Question 2: Should I use given resolution or calculated resolution for my LSB value?

It's important to recognize the the resolution provided in the ARINC 429 spec is an approximation so you can't necessarily use that exactly as it is.
From the commentary in section 2.1.6 Data Standards

For convenience, all binary word ranges in
Attachment 2 are shown as whole binary numbers
rather than such numbers less one least significant
bit value. Also, the resolutions shown are
approximate only. Accurate resolutions can be
determined, if required, by reference to the range
values and numbers of significant bits for the words of
interest.

In order to provide a range of 1.5 to 20, the label will have an actual range of 0-32, which with 11 significant bits, will provide an actual resolution of $\frac{32}{2048} = 0.015625$ (approximated to 0.016 in the ARINC 429 spec)